Hydraulic construction and method for building same

ABSTRACT

The invention relates to an improved hydraulic construction such as a quay structure, work-platform or dolphin, which is built on the bottom of the sea and comprises an above-water structure supported by supporting elements and also a method for building such constructions. The main features of the invention reside in that the construction is anchored in the bottom of the sea by means of substantially vertical prestressed elements, which are secured to anchor elements grouted under the bottom of the sea and forming a counter-balance for the tensile forces acting in the prestressed elements. This provides a stable construction which could be subjected to considerable lateral forces without losing its stability since the support elements will be subjected to compressive forces proportional to the tensile forces. The invention also provides light and simple constructions since the lateral forces acting on the construction must be resisted by big masses contained in the hydraulic construction.

United States Patent Cappe [451 Apr. 4, 1972 [54] HYDRAULIC CONSTRUCTION AND Attorney-Walter Becker METHOD FOR BUILDING SAME [57] ABSTRACT [72] Inventor: Carl T. Cappe, Enebyberg, Sweden The invention relates to an improved hydraulic construction Asslgnee: Nya Asia" Stockholm, Sweden such as a quay structure, work-platform or dolphin, which is [22] Filed; No 19, 1969 built on the bottom of the sea and comprises an above-water structure supported by supporting elements and also a method PP 87 ,0 5 for building such constructions. The main features of the invention reside in that the construction is anchored in the bot- [52] U.S. Cl ..6l/46 tom of the sea by means of substantially vertical presnessed [51] Eozd 21/00 elements, which are secured to anchor elements grouted 58 Field of Search ..6l/4652 Sea and fmmmg the tensile forces acting in the prestressed elements. This pro- [56] References Cited vides a stable construction which could be subjected to considerable lateral forces without losing its stability since the UNITED STATES PATENTS support elements will be subjected to compressive forces proportional to the tensile forces. The invention also provides 2,901,890 9/1959 Hutchrson ..6l/46 light and simple constructions Since the lateral forces acting 2933398 4/1960 UPSOn on the construction must be resisted by big masses contained 3,255,591 6/1966 Thornley ..6 1/46 in the hydraulic construction Primary Examiner.l. Karl Bell 10 Claims, 8 Drawing Figures sum 2 0F 3 PATENTEU R 4 I972 (Err/fa & 8 //b HYDRAULIC CONSTRUCTION AND METHOD FOR BUILDING SAME The present invention relates to a hydraulic construction such as a quay structure, work-platform or dolphin frictionan above-water structure, which is supported by supporting elements resting in or on the bottom of the sea and a method for building such constructions, which are capable to absorb the great lateral forces arising i.e. from the super-tankers of today and tomorrow.

The anchorage of hydraulic constructions depends mainly on the structure of the bottom of the sea. It is previously known to use a number of raking piles, which support the heavy above-water structure, or to use massive or hollow caissons, which are filled with sand or the like and together with the above-water structure transmit the vertical and horizontal forces to the bottom of the sea. It is also previously known to use lateral anchorages by means of chains, wires or the like, which are secured to a ground anchor resting on the bottom of the sea, or to special anchor piles. However, this latter method of anchorage utilizing lateral wires, which are secured to some kind of anchors permits a certain lateral movement of the above-water construction before the anchors take effect, unless the bottom of the sea is extremely well fitted. Such lateral movements are usually not permitted in quay structures and therefore this kind of anchorage is only used in dolphin constructions and where the lateral forces are small.

The main object of the present invention is to eliminate the drawbacks in the above mentioned constructions and to solve the problems arising by the increasing demands of big draught quay structures in an economically and technically satisfactory way. The constructions of this kind should be able to absorb lateral forces of more than 600 tons, which could arise either from ships or from waves and ice.

Another object of the present invention is to use relatively light constructions which simultaneously have an improved stability and shock-absorbing capability, compared with those now in use.

In accordance with these and other objects of the method according to the invention the construction is anchored in the bottom of the sea by means of at least one substantially vertical prestressed element, which is secured to at least one anchor element, disposed at a certain depth below the bottom of the sea, whereby the weight of the wedge-shaped part of the bottom of the sea above the anchor element could be accurately measured and forms a counter-balance for tensile forces in the prestressed element, which give rise to compressive forces in the support elements.

The prestressed elements are preferably grout anchored in the bottom of the sea in such a manner that the anchor elements form a continuous anchor unit.

The invention also relates to a method for building a hydraulic construction and this method is substantially characterized in that the upper ends of the piles, forming the support elements, are cast in a reinforced concrete slab with recessed tubes, through which guarding or guiding tubes for the prestressed elements are sunk to the bottom of the sea whereafter grout hole drilling is efiected through these tubes.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiments of the invention as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a sectional view of a dolphin in which the supporting elements are resting in the bottom of the sea and on rock and the anchor elements are secured in the material above the rock.

FIG. la is a sectional view of one of the prestressed elements according to FIG. 1.

FIG. 2 is a sectional view of a dolphin in which the supporting elements are resting on rock and the anchor elements are secured in the rock.

FIG. 3 is a sectional view of a further type of dolphin where the supporting elements are constituted by columns, in which the prestressed elements are embedded.

FIGS. 4a-c are diagrammatic views showing the different forces acting on a dolphin.

FIG. 5 is an upper view of a pier construction according to the invention to which two ships are moored.

In Fig. 1, which shows a dolphin e.g. forming part ofa quay structure, the above-water construction comprises a quay deck 2 with fender wailing 4 built up by means of a frame work 6 of steel. Mooring hooks 8 could for instance be disposed on the quay deck 2. This construction could be supported by a concrete slab 10, which in turn is supported by raking piles l2 resting on the ground 20. In this specific embodiment the bottom of the sea is constituted by cohesive materials 14 and frictional materials 16 below which a moraine deposit 18 is situated next to the rock 20. The piles 12 are brought down to the rock but certain piles could naturally rest on stones 22 as indicated on the drawing. From the concrete slab l0 prestressed elements 24 are leading through the cohesion material 14 and are secured in the friction material layer 16 by means of grouted anchor elements 26, which are disposed at substantially the same level in very close relationship. The prestressed elements are stretched by means of conventional stretching devices 28 such as turnbuckles whereby the piles 12 will be subjected to pressure forces. The dotted lines 30 on both sides of the dolphin and along the bottom of the sea indicate the free space, which is available outside the construction.

The connection between the concrete slab l0 and the superstructure could be effected by means of bolt-joints 0r sprued iron. If the superstructure is made of steel, it could be formed as a closed construction to better resist corrosion attacks. The prestressed elements could be paststressed by means of the stretching devices 28.

If the rock is situated relatively close to the bottom of the sea meaning that the friction or cohesion-material layers are relatively thin the prestressed elements 24 are, in conformity with Fig. 2, secured in the rock by means of grouted anchors 26 and the piles are preferably resting on the rock. For the rest the construction could be the same as that shown in FIG. 1.

FIG. 3 shows a different kind of dolphin in which concrete columns are supported on the rock 20. The prestressed elements 24 are leading through the columns 32 and secured to the grouted elements 26 in the rock.

The grouted anchors 26 according to FIGS. 1-3 are so formed that they separately or together are disposed in very close relationship at the same level below the bottom of the sea, which is forming a wedge-shaped part 34 as indicated by the dotted lines in the drawings. By taking samples from the bottom of the sea the weight and internal frictional angle a of the frustrum cone can be accurately measured.

If the prestressed elements are subjected to a stretching force, a compressive force will be transmitted to the supporting elements. FIG. 4 shows a very simple loading graph in which the concrete slab 10 supported by the raking piles 12 is subjected to a lateral force H. The forces acting on the construction are with the exception of the lateral force H the weight G of the construction and the prestressing force F. The loads acting on the piles have been designated P, and P According to FIG. 4b showing the unloaded construction the sum of the weight G and the prestressing force F could be divided into two components P" and P,, which illustrate the compressive forces acting on the piles. The force F could be so chosen, that at maximum occurring lateral load H, the piles on one side of the construction will be completely relieved, meaning that the compressive forces on said one side equal zero, without the loss of stability in the construction. This loading graph is illustrated in FIG. 40 where the compressive force F, equals zero when the horizontal force H amounts to the maximum permitted value. The number of prestressed elements could of course be varied in relation to the function of the construction and the calculated lateral forces.

FIG. 5 shows an application of the construction according to the invention in an oil loading pier with the pipes running in a tunnel 50 beneath the bottom of the sea. The pier is formed by separate units 60 interconnected by means of narrow decks 52 and anchored according to the invention. These units could comprise four moor units 60 for the ships 62, four load absorbing units 60" and a loading and unloading unit 60' in which the pipes 50 are opening up. The invention has thus provided a much simpler and consequentiy cheaper construction than those previously known. This is due to the fact that the supporting elements e.g. the piles and the columns, are of a simple design while simultaneously the number of the structural elements will be reduced. Moreover, the above-water construction can be built easier and simpler than previous structures where the supporting elements and the superstructure must transmit the vertical and horizontal forces to the bottom of the sea. A hydraulic construction according to the present invention could thus replace all present heavy quay structures. According to the invention, the division of one deck in several self-supporting units will be facilitated and each unit will in itself be completely stabile even when it is subjected to a maximum load. Consequently, it will be possible to limit the deck area to a minimum and the decks could preferably be prefabricated or built up ashore where it is easy to furnish them with fender wailing, moore hooks, electrical installation, etc. and could then be mounted as a complete construction on the concrete slab by means of sea-going cranes or the like.

The method of building the construction is moreover very simple, since the upper ends of the piles 12 are cast in the concrete slab 10, which is provided with recessed tubes through which guarding and guiding tubes are sunk to the bottom of the sea and the grout hole drillings are effected. The insertion of the prestressed elements could then be effected in a conventional manner. When the mortar in the anchor elements has received sufficient strength the prestressed elements are teststrained with a load, which e.g. could be percent greater than the intended prestressing force. In some cases it could be suitable to unload the prestressed elements after the test strain e.g. to half of the value in order to decrease the number of piles,

The prestressed elements may for instance consist of steel wires 36 (see FIG. 1a) which suitably could be protected against corrosion by means of an internal guarding tube 40 in which a rubber-like compound 38 for instance epoxy-tar is grouted. The tar could be given such properties that even after its solidification it will remain elastic and will adhere excellently to the prestressed elements. Between an external guarding tube 42 and the interior guarding tube 40 grout mortar 44 is introduced to give the external steel tube 42 enough strength to resist external forces for instance from waves and ice pressure. it is, of course, to be understood that the present invention is, by no means, limited to the specific structure shown in the drawings, but that also other modifications using the principle of the invention are possible within the framework of the present invention.

lclaim:

1. In a hydraulic construction, such as a quay structure, work-platform or dolphin, comprising an above-water structure, which is supported by supporting elements resting in or on the bottom of the sea, the improvement wherein the construction is anchored in the bottom of the sea by means of at least one substantially vertical prestressed element, which at one end is secured to at least one anchor element, disposed at a certain depth below the bottom of the sea, and at the other end is prestressed and secured in the above-water structure, thereby giving rise to compressive forces in the support elements, the arrangement of said at least one prestressed element enabling a weighing operation, in which the weight of a wedge-shaped part of the bottom of the sea above the anchor element, which is forming a counter-balance for tensile forces in said prestressed element, can be tensile tested and accurately measured.

2. The construction according to claim 1, wherein the anchor elements are formed by grouted anchors.

3. The construction according to claim 1, wherein several prestressed elements are secured to several grouted anchor elements substantially forming a continuous unit beneath the bottom of the sea.

4. The construction according to claim 1, wherein the supporting elements are formed by raking piles the upper ends of which are cast in a concrete slab on which the prestressed elements are acting.

5. The construction according to claim 4, wherein the piles are resting on rock and the prestressed elements are grouted in the rock.

6. The construction according to claim 4, wherein the piles are passing through a layer of friction soil and supported by a solid substratum below the friction soil and the prestressed elements are grout anchored in the friction soil.

7. The construction according to claim 1, wherein the supporting elements are constituted by columns through which the prestressed elements are leading and secured to anchor elements grouted in the rock on which the columns are resting.

8. The construction according to claim 1, wherein the support elements are constituted by raking piles through which the prestressed elements are leading.

9. The construction according to claim 1, wherein the prestressed elements are leading through an interior guard pipe and surrounded by a rubber-like grout compound.

10. The construction according to claim 9, wherein the interspace between the interior and an exterior guard pipe is filled with grout mortar. 

1. In a hydraulic construction, such as a quay structure, workplatform or dolphin, comprising an above-water structure, which is supported by supporting elements resting in or on the bottom of the sea, the improvement wherein the construction is anchored in the bottom of the sea by means of at least one substantially vertical prestressed element, which at one end is secured to at least one anchor element, disposed at a certain depth below the bottom of the sea, and at the other end is prestressed and secured in the above-water structure, thereby giving rise to compressive forces in the support elements, the arrangement of said at least one prestressed element enabling a weighing operation, in which the weight of a wedge-shaped part of the bottom of the sea above the anchor element, which is forming a counter-balance for tensile forces in said prestressed element, can be tensile tested and accurately measured.
 2. The construction according to claim 1, wherein the anchor elements are formed by grouted anchors.
 3. The construction according to claim 1, wherein several prestressed elements are secured to several grouted anchor elements substantially forming a continuous unit beneath the bottom of the sea.
 4. The construction according to claim 1, wherein the supporting elements are formed by raking piles the upper ends of which are cast in a concrete slab on which the prestressed elements are acting.
 5. The construction according to claim 4, wherein the piles are resting on rock and the prestressed elements are grouted in the rock.
 6. The construction according to claim 4, wherein the piles are passing through a layer of friction soil and supported by a solid substratum below the friction soil and the prestressed elements are grout anchored in the friction soil.
 7. The construction according to claim 1, wherein the supporting elements are constituted by columns through which the prestressed elements are leading and secured to anchor elements grouted in the rock on which the columns are resting.
 8. The construction according to claim 1, wherein the support elements are constituted by raking piles through which the prestressed elements are leading.
 9. The construction according to claim 1, wherein the prestressed elements are leading through an interior guard pipe and surrounded by a rubber-like grout compound.
 10. The construction according to claim 9, wherein the interspace between the interior and an exterior guard pipe is filled with grout mortar. 